In the Mishima story, “Patriotism,” the characters pay homage to what is translated as the “god shelf.”
“On the god shelf below the staircase, alongside the tablet from the Great Ise Shrine, were set photographs of their Imperial Majesties, and regularly every morning , before leaving for duty, the lieutenant would stand with his wife at this hallowed place and together they would bow their heads low. The offering water was renewed each morning, and the sacred sprig of sasaki was always green and fresh. Their lives were lived beneath the solemn protection of the gods and were filled with an intense happiness which set every fiber in their bodies trembling.”
- Yukio Mishima, Patriotism
The “God Shelf” is a kamidana.
Some kamidana seem to be quite elaborate, while others are simple and have very clean lines.
There are some images of a very simple antique kamidana here, and an internet search will yield a wide variety of them.